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When Not to Use the Mean
Lack of scientific
relevance
–The mean is not
defined for nominal data
–The mean is sensitive
to differences that occur only in the tail of the
distribution
•E.g., increasing the
jackpot in Lotto makes one person richer, but most people
still lose
–Small differences may
not be of scientific interest
•Extend life expectancy
by 24 hours
•Decrease average
cholesterol in patients with familial hypercholesterolemia by 20
mg/dl